Electromagnetic rail brake for railroad vehicles

ABSTRACT

An electromagnetic rail brake for railroad vehicles travelling on rails equipped with inductive signal control and having sensors located laterally and below the top surface of a rail has a rod of ferromagnetic material attached thereto with the rod extending the length of the magnet pole pieces. The rod is positioned laterally and downwardly with respect to the faces of the pole pieces toward the sensors. In this position, the rod is a conductor for any stray magnetic fields emanating from the rail brake or the sensors.

United States Patent [191 Tolksdorf Apr. 23, 1974 ELECTROMAGNETIC RAIL BRAKE FOR RAILROAD VEHICLES Giinter Tolksdorf, Hagen, Germany Knorr-Bremse GmbH, Munich, Germany Filed: Oct. 5, 1972 Appl. No.: 295,214

Inventor:

Assignee:

[30] Foreign Application Priority Data Nov. 15, 1971 Germany 2156657 US. Cl 188/165, 335/304 Int. Cl B60t 13/74 Field of Search 303/3; 310/93; 335/304;

References Cited UNITED STATES PATENTS 12/1962 Hofman 335/304 2,207,295 7/ l 940 Latshaw 188/165 Primary Examiner-Duane A. Reger Attorney, Agent, or Firm-Edmund M. .laskiewicz 7 Claims, 3 Drawing Figures Q APR 23 1974 SHEET 1 BF 3 F UOQQ QO mmmms m4 SHEET 2 [IF 3 FIG. 2

ELECTROMAGNETIC RAIL BRAKE FOR RAILROAD VEHICLES The present invention relates to an electromagnetic rail brake for railroad vehicles travelling on rails equipped with inductive signal control and having sensors located laterally and below the top surface of a rail, more particularly, to the elimination of interference between any stray magnetic fields emanating from the rail brake or the sensors.

In the railway signalling art, it has been known to employ an inductive signal control system which includes a number of sensors arranged laterally and below the top surface of a rail. When railroad vehicles having electromagnetic rail brakes travel on rails equipped with inductive signal control, false control systems may be emitted in the event the sensors are actuated by a variation in their magnetic field during the passage of railroad vehicles. Such a signal would indicate the passage of the railroad vehicle and possibly its direction of travel. It is known that under such circumstances a sensor has released a signal indicating a false direction of travel of a passing railroad vehicle whose electromagnetic rail brake was switched on at that time. Such erroneous indications are particularly frequent in those situations where the rail brake magnet of the electromagnetic rail brake consisted of an eddy-current brake magnet. The use of shields for the sensors has not been particularly satisfactory since such a shielding arrangement becomes very costly when the number of sensors employed in a rail system are considered.

It is therefore the principal object of the present invention to provide a novel and improved electromagnetic rail brake for railroad vehicles travelling on rails equipped with inductive signal control and having sensors located laterally and below the top surface of a rail.

It is another object of the present invention to provide such an electromagnetic rail brake which cannot induce the emission of false signals in the sensors of the inductive signal control.

The objects of the'present invention are attained and the disadvantages of the prior art as discussed above are eliminated by the electromagnetic rail brake of the present invention. According to one aspect of the present invention there is disclosed an electromagnetic rail brake for railroad vehicles travelling on rails equipped with inductive signal control and having sensors lo cated laterally and below thetop surface of a rail. The rail brake has a magnetic means positioned immediately above the rail top surface. A rod of ferromagnetic material is attached to the rail brake and extends the length of the magnet means. The rod is positioned laterally and downwardly from the magnetic means toward the sensors so that the rod is a conductor for any stray magnetic fields emanating from the rail brake or the sensors.

The rod is provided with a straight central portion along the length of the magnetic means and both ends of the rod are bent upwardly and obliquely to approximately the centers of the end surfaces of the magnet means. The bent ends of the rod are rigidly attached to plates adjustably mounted on the ends of the magnet.

Other objects and advantages of the present invention will be apparent upon reference to the accompanying description when taken in conjunction with the following drawings, which are exemplary, wherein;

FIG. 1 is a side elevational view of an electromagnetic rail brake incorporating the present invention;

FIG. 2 is a front and elevational view of the rail brake of FIG. 1; and

FIG. 3 is a top plan view of the rail brake of F IG. 1.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views a specific embodiment of the present invention will be described in detail.

In FIG. 1 there is illustrated a rail brake magnet l of a known structure which is employed in an electromagnetic rail brake as known in the art. The magnet 1 comprises a plurality of poles 2 which are shaped at their lower ends into pole pieces 3 which are positioned immediately above the top surface 4 of a rail indicated at 5 in FIG. 2. When the electromagnetic rail brake is actuated, the magnet 1 will be moved into contact with the surface 4 of the rail.

A sensor which is a component of the inductive signal control system is indicated at 6 in FIG. 2. The sensor 6 is positioned laterally to and below the rail top surface 4 in such a manner that the flanges of the wheels of a passing railroad vehicle will influence or modify a magnetic field originating in the sensor 6. The sensor 6 may actually comprise a plurality of separate components positioned closely one following the other parallel to the longitudinal axis of the rail so that the direction of travel of the railroad vehicle can be determined from the sequence of pulses of the signals released by these separate sensor components.

The rail brake magnet 1 has ends 7 with each end being provided with two bolts 8 whose axes are in parallel with the longitudinal direction of the brake magnet I. A plate 9 having a pair of slots 10 therein is attached to each end 7 of the magnet by means of the bolts 8 being inserted in the slots 10. The slots 10 permit a certain vertical adjustment of the end plates 9 with respect to the rail brake magnet 1. Thus, it is only necessary to loosen slightly the bolts 8 to enable a vertical adjustment of the end plates. 7

A rod 11 of a ferromagnetic material has a central portion 12 which extends along the entire length of the brake magnet l. The ends of the rod are bent upwardly and obliquely at 13 and these bent ends are welded to the end plates 9. The rod 11 has a rectangular crosssection and the central section 12 of the rod is positioned such that the shorter dimension edges are substantially horizontal as can be seen in FIG. 2. As a modification, the rod may also have a circular cross-section or a trapezoidal cross-section which is particularly suitable for attaining maximum effect with optimum utilization of material.

The central portion 12 of the rod is disposed laterally and downwardly with respect to the pole pieces 3 in the direction of the sensor 6 as also may be seen in FIG. 2. Thus, when the electromagnetic brake is actuated, the central section 12 of rod 11 will then be in a position beside the head of rail 5 wherein the rod can pass closely above the sensors 6 arranged beside the rail.

During the operation of the electromagnetic rail brake, the central section 12 of the rod 11 becomes a very good conductor in comparison with the surrounding atmosphere for any stray magnetic field emanating laterally from the rail brake magnet 1. Thus, the stray lines of flux from such a magnetic field will be contained for the most part within the section 12 of the rod.

In a similar manner, the central section 12 of the rod is a good conductor for the magnetic field emanating from the sensors 6. Thus, stray lines of flux from this field are largely concentrated in the rod section 12. Since the stray magnetic fields of both the rail brake magnet and the sensor are both largely concentrated in the rod section 12 these stray fields cannot exert a reciprocal effect between themselves such that false signals would be released from the sensor 6. When the sensor 6 is passed by a railroad vehicle whose electromagnetic brake is actuated, at the most, the sensor can be induced to release a signal indicating the passage of the railroad vehicle in the correct direction of travel. On the other hand, the possibility of sensor 6 being induced by rail brake magnet l to release a signal corresponding to the false direction of travel is prevented even in those circumstances where the brake magnet consists of an eddy-current brake magnet comprising a pole sequence alternating in the longitudinal direction. This is of particular significance should the sensor 6 be utilized for controlling a crossing gate along the rail line travelled by the railroad vehicle. When sensors are used in this manner, it is apparent that the correct direction of travel of the vehicle be indicated at all times and that no false signals indicating a wrong direction of travel be emitted.

Thus it can be seen that the present invention has disclosed an electromagnetic rail brake which effectively prevents the release of falsesignals from sensors of an inductive signal control system wherein the sensors are positioned adjacent the rails over which vehicles equipped with the electromagnetic brake are travelling.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

What is claimed is:

1. An electromagnetic rail brake for railroad vehicles travelling on rails equipped with inductive signal control and having sensors'located laterally and below the top surface of a rail, comprising magnet means positioned immediately above the rail top surface, a rod of ferromagnetic material attached to the rail brake and extending the length of the magnet means, said rod being positioned laterally and downwardly from said magnet means toward the sensors whereby the rod is a conductor for any stray magnetic fields emanating from the rail brake or the sensors.

2. An electromagnetic rail brake as claimed in claim 1 wherein said rod has a straight central portion along the length of the magnet means and both ends are bent upwardly and obliquely to approximately the centers of the end surfaces of the magnet means.

3. An electromagnetic rail brake as claimed in claim 2 and comprising a plate mounted on each end of said magnet means, the bent ends of said rod being attached rigidly to said end plates.

4. An electromagnetic rail brake as claimed in claim 3 wherein said plates are adjustably mounted thereon.

5. An electromagnetic rail brake as claimed in claim 3 wherein said end plates are each parallel to the respective ends of the magnet means.

6. An electromagnetic rail brake as claimed in claim 1 wherein said rod has a rectangular cross-section, the central portion of the rod being disposed such that the shorter dimension edges are horizontal.

7. An electromagnetic rail brake as claimed in claim 1 wherein said rod has a circular or trapezoidal crosssection. 

1. An electromagnetic rail brake for railroad vehicles travelling on rails equipped with inductive signal control and having sensors located laterally and below the top surface of a rail, comprising magnet means positioned immediately above the rail top surface, a rod of ferromagnetic material attached to the rail brake and extending the length of the magnet means, said rod being positioned laterally and downwardly from said magnet means toward the sensors whereby the rod is a conductor for any stray magnetic fields emanating from the rail brake or the sensors.
 2. An electromagnetic rail brake as claimed in claim 1 wherein said rod has a straight central portion along the length of the magnet means and both ends are bent upwardly and obliquely to approximately the centers of the end surfaces of the magnet means.
 3. An electromagnetic rail brake as claimed in claim 2 and comprising a plate mounted on each end of said magnet means, the bent ends of said rod being attached rigidly to said end plates.
 4. An electromagnetic rail brake as claimed in claim 3 wherein said plates are adjustably mounted thereon.
 5. An electromagnetic rail brake as claimed in claim 3 wherein said end plates are each parallel to the respective ends of the magnet means.
 6. An electromagnetic rail brake as claimed in claim 1 wherein said rod has a rectangular cross-section, the central portion of the rod being disposed such that the shorter dimension edges are horizontal.
 7. An electromagnetic rail brake as claimed in claim 1 wherein said rod has a circular or trapezoidal cross-section. 